Have you ever tried doing bench presses to the neck? I had read about them before and some people swear by them, so I've been trying them during my chest workouts. It's essentially where you lower the bar to about where your clavicle is; normally I lower the bar to about my nipple line. It's a little harder, since it's a different angle and I can feel more (muscular) stress in the top of my chest, but I really don't know exactly what to think of it. So if anyone else has had good results from doing these, let us know!
I think genetics has a lot to do with how your chest shapes up as it grows. Some say you can't really target the upper areas of the chest (namely the clavicular head), but other people swear by incline presses. Heck, Arnold says you can work the upper, lower, middle, inner and outer pectorals while someone who's studied exercise physiology literature would call him crazy! It's a debatable topic indeed.
I would simply suggest to focus on overall chest growth, rather than trying to target and isolate specific regions. As your chest grows, your upper chest will naturally grow too, as long as your genetics allows for a full chest shape. Some people are just naturally more apt to have fuller, wider chest than others. For instance, thanks to genetics, I will never have that square chest look. However, I can still work to develop my chest to it's maximum potential. I'm not the type of person to say incline presses are totally useless; I just make the bulk of my chest routine centered around flat barbell presses because it allows me to use maximum weight. After barbell presses I do some incline DB presses and DB pullovers, finishing with some chest dips where I do slow negatives to really stretch the pectorals! I am a firm believer in the benefits of good stretching techniques, before training (dynamic stretches), during the exercises themselves, and after training (static stretches).
On a side note, I'm really fond of doing supersets with incline DB presses and DB pullovers. On the incline presses I explode upwards with the weight and lower it slowly (2-3 seconds). On the DB pullovers I really concentrate to involve the serratus as much as possible and it's paying off as my serratus are becoming more and more prominent. Just thought I'd share!
Good luck to all in their quest to develop the illusive upper chest!